Problem with Carrier Weathermaker 9200

Hi,

I'm a DIY chatroom n000b, as well as a HVAC n000b, but I am an engineer by trade, so I'm hoping to fix my problem without the aid of a service tech.

Yesterday, our furnace (Carrier Weathermaker 9200) stopped heating our house. I've been trying to diagnose and have been able to get a series of error codes, as well as being able to repeat the process.

When I shut off the power to the furnace, then power it back on, the blower blows for 90 seconds, while I receive the LED error code 12 (which stands for "Blower on After Power Up"). The The technical description of this error is "Blower runs for 90 seconds, if unit is powered up during a call for heat (R-W closed)."

Then the blower shuts off, and I get the LED continously on for 10 - 15 seconds while PBT/Control motor starts up. While the PBT is on, I receive the LED error code 34, which is "Ignition Providing Failure" - tech. description is "Control will try 3 more times before a lockout #14 occurs. If flame signal lost after trial for ignition period, blower will come on for 90 second recycle delay."

The furnace does indeed try to ignite 3 more times, as I can hear the ignition tripping. After the 3 tries, the control seems to shut down again, and I receive the LED error code 14, which is "Ignition Lockout - Control will reset after 3 hours."

If I shut off the power to the furnace and power back on, I can repeat this entire process without having to wait at all. However, I'm not sure what steps I need to take in order to service the furnace. I've tried disconnecting the thermostat from the "R" thermostat lead, I removed the control panel and replaced to reset the error codes. I've also tried sucking out the water trapped in the condenser by mouth to unclog whatever might be clogged; all to no avail.

With all that being said, I was hoping someone here may have encountered the same problem, or could offer some suggestions on how to service and troubleshoot.

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Problem with Carrier Weathermaker 9200

Hi Skip,

TY for the speedy reply. I'm not sure, I don't see any light or red glow, and I'm not sure where that part is located. I believe everything is enclosed and I'm not sure I'd be able to see any flame or glow even if it was working properly. Do you know where the flame ignoitor is located?

Problem with Carrier Weathermaker 9200

Problem with Carrier Weathermaker 9200

I located the Burner box, and I see 2 wires going to what would be the fuse(?) (actually the 'fuse' looks more like a sensor) which is located on the outside of the burner box. The burner box is a round aluminum enclosure and there's no way to see what's going on inside. How might one re-ignite the ignitor? The instructions on the furnace says it ignites automatically, do not attempt to light. Is there a way to manually reset the ignitor, or would I need to replace the burner box?

Problem with Carrier Weathermaker 9200

You should have 2 white wires going into the burner box at the top of the furnace. These wires should have an inline plug. If you have a meter, this is a good place to check for voltage from the circuit board. Should be line voltage. You can also check the resistance on the ignitor, no resistance is bad. These ignitors are generally a real bear to remove. Sometimes the bracket that holds the ignitor will break have to be replaced. Carrier makes an upgraded bracket that isn't much better than the original. Usually requires removing the gas train and the burner box to repair.

Problem with Carrier Weathermaker 9200

Thanks for all the replies. On my unit, the part is labeled as the burner enclosure, I believe (small circular device with the sensor attached). The large box at the top of the furnace has a small clear circular window in which you can see through to the heating coils. There is definitely no red glow through this window, so I'm looking into buying a replacement burner enclosure, which I assume ignites the furnace. Is this the right direction to go, per your expertise?

Problem with Carrier Weathermaker 9200

Problem with Carrier Weathermaker 9200

I found the ignitor in the back of the burner box, but it's not easy to access at all, I think I would have to disassemble the entire burner box. I was able to check it with a meter and I do have resistance. I'm not sure what to do from here, but thanks for all the help.

Problem with Carrier Weathermaker 9200

The HSI/hot surface igniter should have between 50-80 ohms resistance. If it is burnt out it will have infinite or over 100 ohms and needs changing. It is VERY fragile and VERY difficult to get at. Is held in by a spring clip and must have the little red gasket which surrounds it put back in place properly or other problems will occur. Must get the proper HSI from Carrier as others won't fit. When the ventor fan starts it has a pre-prurge cycle and then there should be 110 volts going to the HSI/white molex plug which you can check if you are careful. Don't want your friends calling you Sparky. You may want to get a pro to change it or pull the whole burner box out as most people will break one B4 they get the knack of that miserable endeaver. Have done lots of them myself.

Problem with Carrier Weathermaker 9200

Thanks for the reply Yuri. 8 hours later I'm still pluggin' away it. I've made some progress today and have found that ignitor glows red intermittently, so I can say with certainty that the ignitor is still good. What I'm now confused about is the intermittency, and when the ignitor does glow red/orange, why the burners don't ignite.

Problem with Carrier Weathermaker 9200

The resistance of the igniter is very important. If it is too high then it won't glow at the correct temp/red enough and that can cause poor or no ignition. It may take too long to glow. The gas valve only opens for a couple of seconds and then shuts down according to the control timer. Long story short: the timing off all this is critical, if the igniter takes too long to get to the right color it misses its opportunity to light the gas properly.

Problem with Carrier Weathermaker 9200

Hi,

Just wanted to give a big thanks to everyone who responded. I finally got my issue resolved today; and all of you were 100% correct, it was a bad surface igniter. You all helped me diagnose the problem, which saved me on the initial estimate. For future reference (for anyone who's interested), Carrier will not sell the surface igniter to the general public, they only sell to licensed technicians(i guess they don't want the general public messing around with combustion for insurance purposes). The tech came out and installed the surface igniter for a total charge of $140 bucks, best price in Baltimore. Also, i dunno how improper it is to mention the company, but the company was called Allteck Heating and Cooling, located in Baltimore, Maryland. If anyone has a problem and is in the Baltimore area, I would highly recommend them. They are a family-owned business, 4 guys, and they diagnosed my problem over the phone and didn't charge for the initial estimate.